TeXquisite 0.131.0 - reuse unchanged page canvases

Windows 0.131.0 keeps unchanged page canvases attached after exact worker-cache validation, avoiding repeated allocation and painting. Fonts, page size, resolution, saved source, compiler and Build/Export are unchanged.

Controlled cloud trials used this same packaged binary with reuse disabled/enabled. Median text edits improved from 122.5 to 99.5 ms, inline math from 128 to 94 ms, and sustained typing from 253.5 to 111 ms. Sustained p95 improved from 371 to 137 ms. The isolated text maximum was 247 versus 265 ms, so this is not an across-the-board worst-case guarantee. These are hidden completed-canvas measurements on a synthetic ten-page lecture, not physical-display or private-document timings.

Validation passed: 100 selected unit/native checks, 29 integration reports, 28 raster/cache pixel cases, 24 actual viewer/full-raster comparisons with zero differences, and seven supplemental ownership/race scenarios. Automatic error recovery, error-counter clearing and navigation on reused pages passed.

See CACHED-CANVAS-SPEED.md for methods and limitations, CACHED-CANVAS-RESULTS.json for raw aggregate data, PROVENANCE-0.131.0.json for source and checksums, and FIRST-RUN.md for installation. The earlier cross-page whole-paragraph prototype remains withdrawn.

Windows x64 portable prerelease; bring an installed TeX Live or MiKTeX. Mac/Linux preview downloads remain on their existing release pages. Corresponding source: https://github.com/complexzeta/TeXquisite/tree/v0.131.0 ; the bundled compiler's corresponding source, patch/build scripts and licenses are included in that tagged tree. This is an unsigned preview build.